Technical Series, No. 17, Part II. U. S. DEPARTMENT OF AGRICULTURE, BXIRE^TJ Om ElSrTO]VIOIL.O&Y. L. 0. HOWARD, Entomologist and Chief of Bureau. CONTRIBUTIONS TOWARD A MONOGRAPH OF THE SCOLYTID BEETLES. 11. PRELIMINARY CLASSIFICATION OF THE SUPERFAMILY SCOLYTOIDEA. A. D. HOPKINS, Ph. D., In Charge of Forest Insect Investigations. Issued January 9, 1915. WASHINGTON: eOVERNMENT PRINTING OFFICE. 1915. Technical Series, No. ^7, Part II. U. S. DEPARTMENT OF AGRICULTURE, BTJRE^^XJ OF EjSTTOlMOLOGrY. L. 0. HOWARD, Entomologist and Chief of Bureau. CONTRIBUTIONS TOWARD A MONOGRAPH OF THE SCOLYTID BEETLES. 11. PRELIMINARY CLASSIFICATION OF THE SUPERFAMILY SCOLYTOIDEA. A. D. HOPKINS, Ph. D., In Charge of Forest Insect Investigations. Issued January 9, 1915. WASHINGTON: GOVERNMENT PRINTTNG OEEICE. 1915. B UREA U OF ENTOMOLOG Y. L. O. Howard, Entomologist and Chief of Bureau. C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. E,. S. Clifton, Chief Clerk and Executive Assistant. F. H. Chittenden, in charge of truck crop and stored product insect investigations. A. D. Hopkins, in charge offorest insect investigations. W. D. Hunter, in charge of southern field crop insect investigations. F. M. Webster, in charge of cereal and forage insect investigations. A. L. QuAiNTANCE, in charge of deciduous fruit insect investigations. E. F. Phillips, in charge of hee culture. A. F. Burgess, in charge of gipsy moth and brown-tail moth investigations. RoLLA P. CuRRiE, iu charge of editorial luork. Mabel Colcord, in charge of library. Forest Insect Investigations. A. D. Hopkins, in charge. H. E. Burke, August Busck, W. D. Edmonston, Josef Brunner, T. E. Snyder, F. C. Craighead, J. M. Miller, S. A. Rohwer, A. G. Boving, C. T. Greene, W. S. Fisher, Jacob Kotinskt, B. T. Harvey, entomological assistants. Carl Heinrich, A. B. Champlain, Wm. Middleton, Mary E. FAUNCEa, Mary C. Johnson, scientific assistants. Morris Chrisman, Geo. Hofer, J. D. Riggs, P. D. Sergent, J. J. Sullivan, Albert Wagner, W. E. Glendinning, J. C. Evenden, F. B. Herbert, P. F. Keen, J. H. Pollock, entomological rangers. Esther H. Hart, artist. Margaret Fagan, Elizabeth Ritchie, Maude Taylor, Edna O. Haslup, Pearl L. Boone, preparators. "Resigned April 1, 1914. CONTENTS. Introduction 165 Position of the Scolytoidea 167 . General anatomy. '. 168 Taxonomy 169 Morphological characters 169 Superfamily characters 169 Family characters 170 Subfamily characters 170 Generic characters 171 The antennae 171 The eyes 174 The mouthparts 174 Characters in general . 175 The body 175 Form 175 Color 176 Vestiture 176 Sculpture 176 Armatures ..:.... 176 Head 177 Prothorax 177 Mesothorax 177 Metathorax 178 Legs 179 Elytra 179 Posterior wings 179 Abdominal tergites 180 Abdominal spiracles 181 Abdominal sternites 182 Stridulating accessories 182 Internal anatomy 183 Digestive system 183 Proventriculus 183 Reproductive organs 184 The reproductive organs of the male 184 Posterior elements 185 Anterior and median elements 190 Variations and combinations of the elements 190 Terminology of the reproductive organs 192 Classifications based on the reproductive organs 194 Secondary sexual characters 195 The pupae 196 The larvae 197 The eggs 197 The embryo 197 III . IV CONTENTS. Taxonomy—Continued. Page. Physiological characteristics 198 General habits 198 Classification according to habits 198 Food habits of the adults 199 Food habits of the larvae 199 Pupal habits 199 Flight habits 200 Social habits 200 Galleries 201 Terminology of the galleries 202 Classification of the galleries 204 Egg galleries 204 Larval mines 204 Types and subtypes of egg galleries 205 Relation of types of galleries to the subfamilies and families. 206 Taxonomic relation between the beetles and their host plants 207 Part of plant selected by the beetles 207 Condition of the plant 208 Relation of the species of beetles to the systematic position of their host 208 Range of host plants 208 Associations of species of beetles and species of plants 209 Summary of taxonomic evidence furnished by host relations .... 209 Geographical distribution in its bearing on taxonomy 210 Review of taxonomic characters and characteristics 211 Morphological characters 212 Physiological characteristics 213 Correlation of morphological and physiological elements 213 Parallel modifications 214 Reversals 214 Progressive modifications 215 Examples of progressive modification 215 Statistical taxonomy 216 The species 216 Varieties, races, etc 216 The genus 217 Nomenclature 218 Types of genera 219 Genus Scolytus Geoffroy 219 Genus Ips De Geer 220 Genus Tomicus Latreille 220 Genus Hylastes Erichson 221 Genus Cryphalus Erichson 221 Genus Hypothenemus Westwood 221 Genus Polygraphus Erichson 222 Genus Lepisomus Kirby 222 Description of a new genus and species 222 Preliminary classification of the Superfamily Scolytoidea 224 Key to the families 224 Division 1 224 Subdi\dsion A 224 Family Ipidse 224 CONTENTS. V Preliminary classification of the Superfamily Scolytoidea—Continued. Key to the families—Continued. Division I—Continued. Page. Subdivision B 225 Family Scolytidse 225 Family Scolytoplatypodidse 225 Division II 225 Subdivision G 225 Family Platypodidse 225 Family Ipidse. Key to the subfamilies 225 Division 1 225 Subdivision A 225 Subfamily Cryphalinse 225 Subfamily Ipinae 225 Subfamily Corthylinae 225 Subfamily Micracinee 225 Subfamily Webbinse 225 Subdivision B 225 Subfamily Xyloctoninse 225 Division II 225 Subdivision G 225 Subfamily Crypturginae 225 Subfamily Phloeotribinse 225 Subdivision D 225 Subfamily Hylesininse 225 Subfamily Phloeoborinse 225 Family Scolytidse. Key to the subfamilies 225 Division 1 225 Subfamily Coptonotinse 225 Division II 225 Subdivision A 225 Subfamily HexacoLLnge 225 Subfamily Bothrosteminse 225 Subfamily Hyorrhynchinse 225 Subdivision B 225 Subfamily Camptocerinae 225 Subfamily Scolytinae 225 Family Scolytoplatypodidse 225 Family Platypodidse. Key to the subfamilies 225 Division 1 225 Subfamily Platypodinas 225 Division II 225 Subfamily Genyocerinse 225 Subfamily Chapuisinee 225 Position of the principal described genera in the preliminary classification 226 Genera described in 1911-12, not included in foregoing list, but here pro- visionally assigned to the subfamilies 227 Genera of doubtful position 228 Bibliography 229 . ... ILLUSTRATIONS. PLATES Page. Plate IX. Figs. 1-18.—Typical targi and tibiae of the subfamilies of Scoly- toidea 170 X. Figs. l-5a. —Antennae of tyx^ical si^ecies of the subfamilies of Scoly- toidea 170 XI. Figs. 7-lOa. —Antennae of tj^Dical species of the subfamilies of Scolytoidea 170 XII. Figs. 12-lSb. —Antennae of typical species of the subfamilies of Scolytoidea 170 XIII. Figs. l-9b. —Tibiae and tarsi of typical species of the subfamilies of Scolytoidea 178 XIV. Figs. 10-lOb.—Tibiae and tarsi of typical species of the subfamilies of Scolytoidea 178 XV. Figs. 12-15b. —Tibiae and tarsi of typical species of the subfamilies of Scolytoidea 178 XVI. Figs. 16-18b. —Tibiae and tarsi of tyi3ical species of the subfamilies of Scolytoidea 178 TEXT FIGURES. Fig. 9fi. The antenna in scolytoid beetles: Diagram and terminology 172 97. Abnormalities in the antennal funicle of Xylehorus tachygraphus 173 98. Ips emarginatus: Proventricular plate 183 99. Scolytus scolytus: Proventricular plate 183 100. Crossotarsus lecontei: Proventricular plate 183 101. Dendroctonus valens: Membranous and nonchitinous elements of male reproductive organs -. 184 102. Xylehorus saxeseni: Chitinous elements of male reproductive organs. 184 103. Ips emarginatus: Chitinous elements of male reproductive organs 185 104. Pityophthorus sp.: Chitinous elements of male reproductive organs. 186 105. Pityophthorus bellus: End plates and seminal rod of male reproductive organs 186 106. Micracis suturalis: Posterior elements of male reproductive organs. 186 107. Dendroctonus valens : Posterior elements of male reproductive organs 187 108. Scolytus rugulosus: Posterior elements of male reproductive organs . 189 109. Scolytus quadrispinosus: Posterior elements of male reproductive organs 189 110. Crossotarsus lecontei: Posterior elements of male reproductive organs. 191 111. Dendroctonus valens: Female reproductive organs 194 112. Classification of galleries of Scolytoidea 205 VI U. S. D. A., B. E. Tech. Ser. 17, Pt. II. F. I. I., January 9, 1915. CONTRIBUTIONS TOWARD A MONOGRAPH OF THE SCOLYTID BEETLES. II. PRELIMINARY CLASSIFICATION OF THE SUPERFAMILY SCOLYTOIDEA.'^ By A. D. Hopkins, Ph. D., In Charge of Forest Insect Investigations. INTRODUCTIOSr. The object of this contribution is to discuss the taxonomy and present a preUminaiy classification of the families and subfamiUes of tlie scolytoid beetles of the world. The discussion and classifi- cation are based on a study of representatives of about 122 described and undescribed genera and about 1,000 species of North America and other countries, in the collections of the U. S. National Museum and certain other museums and institutions of this country. The types of North American species described by Zimmermann, LeConte, Fitch, Harris, Schwarz, Ulke, and, with a few exceptions, those of other North American authors, have been studied by the writer. Nearly all of the North American species described by Eichhoff are represented in the U. S. National Museum collections by specimens sent by him to the writer and to Dr. C. V. Riley. Many of these specimens are from the type series not only of North American but of many foreign species described by Eichhoff. Cen- tral and South America, the West